My cat has one dilated pupil and one slit. What's wrong with his eye?

There is anisocoria (the two pupils are unequal in size) and possibly ptosis of the upper eyelid (the eyelid cannot open normally) on the left side (where the pupil is bigger). There are many causes that can provoke this presentation: -Corneal injury such as an ulcer. -Disease or injury to the brain or to the nerves running to the affected eye, such as Horner’s syndrome. -Glaucoma, a disease in which there is increased pressure within the eye (the pupil in the affected eye will be dilated). -Uveitis, or inflammation of the interior of the eye (the pupil in the affected eye will usually be constricted). -Retinal disease. -Scar tissue formation between the iris and the lens (called posterior synechia), a condition that may develop following uveitis. -Iris atrophy (a decrease in the amount of tissue within the iris) usually a degenerative change associated with aging. -Congenital defect of the iris, in which the iris tissue does not develop properly. -Cancer within the affected eye. -Spastic pupil syndrome - a syndrome that may be associated with feline leukemia virus infection. -Other infectious diseases such as feline immunodeficiency virus or toxoplasmosis. Unfortunately is difficult to be more specific than that and a clinical examination at your local veterinarian is essential to confirm these clinical suspicions and treat appropriately. Antibiotics may be needed. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!

Poor guy! It could be a sign of pain or trauma from the event including head or neck trauma, or a side effect of pain medication. If he was bleeding did they find the source of it? Was he given any medications at the clinic (pain medication?) or to take home? Was he appropriate mentally there and then has declined? The problem with kittys getting attacked is that the attacker often shakes them while biting. This can create a lot of shear trauma under the skin that is initially not seen. If no meds have been given i would worry about pain or head trauma. I would recommend calling the clinic that saw him to report this change. The safest thing for these patients is for them to be hospitalized for monitoring because not all problems show up right away. If head trauma is suspected medications may need to be given for this. I hope this helps and thank you for using Petco Pet Education Center, formerly Petcoach!

Hello and thank you for reaching out to Petco Pet Education Center, formerly Petcoach. Small or constricted pupils may be a sign of uveitis, which means inflammation in the front chamber of the eye. This can be due to infectious causes (bacterial/viral/fungal), high blood pressure, immune-mediated diseases or trauma, among other things. Cats with uveitis are often painful, however, and will show squinting of the eyes, will be sensitive to light, are often hiding, etc. It is possible that he has no ocular issues, and that you have just never observed his pupils in a dark room (this is very hard to do!). You can test if he can see by gently motioning toward his eyes with your hand (called a menace response) to see if he blinks. If he is squinting his eyes, has abnormal discharge (yellow/green, thick/mucoid), or very red conjunctiva, I recommend bringing him to your veterinarian to be evaluated. I hope this is helpful!

Horner's syndrome can result due to an ear cleaning if there was damage done to the ear during the cleaning, but it can also result from an ear infection, blunt force trauma, and disease of the eye among other things. If Munna had Horner's syndrome, you would see other symptoms such as drooping of the eyelid of the affected side, the third eyelid would be raised and appear red, and the affected eye may appear sunken. Moon should see a vet for this immediately. It's very serious when one eye suddenly is dilated while the other is not. The vet can diagnose what is causing this to occur, and can treat him for it. Please take him into a vet now.

Thank you for submitting your question regarding Sparky. Horner's syndrome is not a common side effect from anesthesia and it does not frequently happen in young animals. She would need to see her veterinarian to know for sure though. She could have an eye infection or even an ulcer (scratch across the surface of the eye). Anesthesia does dry out the eyes making them more prone to ulcers. It would be a good idea for her to see her veterinarian again if possible as she may need medication. I hope this information helps!

Yes, that is definitely something you should be worried about. What you are seeing is called anisocoria, and when it suddenly appears, it is a medical emergency. This can be due to corneal injury, disease or injury to the brain, disease or injury to the nerves running to the eye, or uveitis among other causes. I would take Ace into an ER vet or find a vet on call to see him ASAP to diagnose what is causing the anisocoria so it can be treated.

Hi, I'm so sorry you and Neo are going through all of this. I believe you use a different spelling of "esophagus" in Australia than we do in the U.S., so I'm going to assume that's what you mean by an O-tube. Figuring out the cause of anisicoria (that's when the pupils aren't the same size) usually involves determining 1.) which eye is the "affected" eye and 2.) whether the pupil is inappropriately dilated or inappropriately constricted. So we'd likely need a bit more information after doing a physical exam to answer the question exactly. However, as Neo is on buprenorphine (that's the "Temvet ilium" you've mentioned) I would say it's *possible* to see neurologic effects such as slight anisicoria on this drug. However, a bigger question/concern would be whether the installation of the E-tube affected nerves in the neck, as this may cause something called Horner's syndrome. I would recommend having Neo re-examined in order to nail down the questions I've outlined above. If the affected eye is on the same side as the E-tube, I would be suspicious that the two are related.